British gas will freeze the price of its standard variable tariff this winter and launch a new deal which allows customers to fix energy prices until March 2019.

The large energy firm will also ensure its customers always get access to its best deals and offer an annual energy health check for customers on the standard rate, to make sure they are on the right tariff.

The price freeze will benefit more than six million customers on British Gas’s standard tariff.

British Gas chief executive Mark Hodges said the firm had been “thinking hard about ways to improve how the energy market works for all our customers”. He added that engineers would be working hard through the Christmas period, including on Christmas Day, to ensure homes stay warm.

Which? managing director of home and legal services Alex Neill said: “While it’s welcome that another big energy supplier is freezing its standard tariff prices, these are generally the most expensive deals on the market and customers should look to see if they can switch to a better deal.

“Energy companies should be doing much more than simply freezing their prices this winter. We want them to set out what they’re doing to genuinely engage with customers who are stuck on these poor-value deals. The government and the regulator must be ready to act if energy companies fail to deliver.”

British Gas also launched its Free Time tariff in July, which gives smart meter customers free electricity on a Saturday or Sunday.